Bug Particle Systems with Lights Bugged

Hello, I recently upgraded my project to Unity version 2019.3.0a5 and my HDRP packages to 6.7.1. I also added the VFX Graph 6.7.1 package to my project when updating.

Pretty much the reason for updating everything was that I wanted to work with the VFX Graph, and my outdated Unity and Pipeline wasn't playing nice with it.

Everything works fine, until I noticed that any Particle System that has a light enabled will cause a gray screen and immense lag if on screen. (VFX Graphs have had no problems, just the older Shuriken particle systems) I've had to disable all of the lights on my particle systems, which is not ideal. Any ideas on what's causing this?

 

Okay, found out that whenever the bug happens, this error is thrown:

Spoiler: Error Log

Code (CSharp):

1. NullReferenceException: Object reference not set to an instance of an object
2. UnityEngine.Experimental.Rendering.HDPipeline.LightLoop.PrepareLightsForGPU (UnityEngine.Rendering.CommandBuffer cmd, UnityEngine.Experimental.Rendering.HDPipeline.HDCamera hdCamera, UnityEngine.Rendering.CullingResults cullResults, UnityEngine.Experimental.Rendering.HDPipeline.HDProbeCullingResults hdProbeCullingResults, UnityEngine.Experimental.Rendering.HDPipeline.DensityVolumeList densityVolumes, UnityEngine.Experimental.Rendering.HDPipeline.DebugDisplaySettings debugDisplaySettings, UnityEngine.Experimental.Rendering.HDPipeline.AOVRequestData aovRequest) (at Library/PackageCache/com.unity.render-pipelines.high-definition@6.7.1-preview/Runtime/Lighting/LightLoop/LightLoop.cs:1809)
3. UnityEngine.Experimental.Rendering.HDPipeline.HDRenderPipeline.ExecuteRenderRequest (UnityEngine.Experimental.Rendering.HDPipeline.HDRenderPipeline+RenderRequest renderRequest, UnityEngine.Rendering.ScriptableRenderContext renderContext, UnityEngine.Rendering.CommandBuffer cmd, UnityEngine.Experimental.Rendering.HDPipeline.AOVRequestData aovRequest) (at Library/PackageCache/com.unity.render-pipelines.high-definition@6.7.1-preview/Runtime/RenderPipeline/HDRenderPipeline.cs:1603)
4. UnityEngine.Experimental.Rendering.HDPipeline.HDRenderPipeline.Render (UnityEngine.Rendering.ScriptableRenderContext renderContext, UnityEngine.Camera[] cameras) (at Library/PackageCache/com.unity.render-pipelines.high-definition@6.7.1-preview/Runtime/RenderPipeline/HDRenderPipeline.cs:1449)
5. UnityEngine.Rendering.RenderPipeline.InternalRender (UnityEngine.Rendering.ScriptableRenderContext context, UnityEngine.Camera[] cameras) (at C:/buildslave/unity/build/Runtime/Export/RenderPipeline/RenderPipeline.cs:72)
6. UnityEngine.Rendering.RenderPipelineManager.DoRenderLoop_Internal (UnityEngine.Rendering.RenderPipelineAsset pipe, UnityEngine.Camera[] cameras, System.IntPtr loopPtr, Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle safety) (at C:/buildslave/unity/build/Runtime/Export/RenderPipeline/RenderPipelineManager.cs:67)
7. UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)
8.  

 

This is related to issue #1059208 in the issue tracker. It was supposedly fixed, but it's back now.

 

I am experiencing this in 2019.3.0b12
Is this a known issue? I couldn't find it in the issue tracker

 

https://issuetracker.unity3d.com/is...on-when-using-particle-system-lighting-module

 

If particle system has light module with one light, light is not seen. Did anyone experience that?

 

Thank you. It seems that it has been an issue after the initial fix since July, so I messed around for a bit and found a temporary fix. Please only implement if you know how to code.

the issue is the light that is passed into the processing loop in LightLoop.cs. I don't have visibility into where the light is assigned and passed as a CullingResults but this is relatively low risk to implement, and definitely less harmful than the null light getting passed around and throwing errors.

in LightLoop.cs PerpareLightsForGPU around line 2030 (will be different depending on build) replace:

Code (CSharp):

1. if (!aovRequest.IsLightEnabled(light.light.gameObject))
2.                                 continue;

with

Code (CSharp):

1. if ((object)light.light != null)
2.                         {
3.                             if (!aovRequest.IsLightEnabled(light.light.gameObject))
4.                                 continue;
5.                         }

this was throwing the error because light.light was null and so gameObject wasn't defined.
then in HDAdditionalLightData.Types.cs at the beginning of the last function:

Code (CSharp):

1. internal HDLightType ComputeLightType(Light attachedLight)  

around line 422, insert:

Code (CSharp):

1. if ((object)attachedLight == null)
2.             {
3.                 return HDLightType.Point;
4.             }

The VFX i use are all point lights, and i didn't test but i assume it probably wouldn't work as intended with other light types, but it's better than nothing.

Again, please only implement if you understand what it is doing.

 

Update on the tracking of this, it is in review: https://issuetracker.unity3d.com/is...em-with-light-module-on-is-added-to-the-scene

 

2019.3.0f1 and HDRP 7.1.6

No errors and rendering of the scene doesn't stop anymore, but the lights don't actually light anything.

 

Any idea when 7.2 might be released?

 

I'm too interested in this

 

it's available now:

 

Still a problem with this when the light prefab used has shadows enabled.